Democrats in Congress are calling for an investigation into the death toll in Puerto Rico from Hurricane Maria following a report released last week that dramatically revised the tally upward.

Fourteen Democratic members of the House Committee on Natural Resources sent a letter to the committee’s chair, Rep. Rob Bishop, R-Utah, asking for a “timely” hearing into the central claim of a new Harvard study that 4,645 people died last year in Puerto Rico as a direct or indirect result of the hurricane.

“This staggering loss of American life and the significant variance from officially reported figures points to the need for further oversight,” read the letter, which included ranking member Raúl M. Grijalva, D-Ariz., as one of its signees. “With hurricane season now upon us, time is of the essence. It is imperative that our country learn from this trying experience and gather any lessons for future planning. Further, it is our responsibility to be honest about the shortcomings of the Trump Administration’s response to this disaster, provide answers to the Puerto Rican people, and take immediate steps to correct any outstanding inadequacies.”

Due to Puerto Rico’s status as a territory, federal oversight of the island falls to the House National Resources Committee. A spokesperson for the committee told Yahoo News that the hearing was tentatively scheduled for July.

The death toll laid out in the Harvard study is 73 times the official government count of 64 and is in line with reports from the island, including interviews with funeral home directors who said last fall that the government numbers were too low. If the number proves accurate, Maria would be the second biggest natural disaster in U.S. history, trailing only a 1900 hurricane that hit Galveston, Texas.

Hundreds of shoes are displayed on June 1 at Puerto Rico’s Capitol in memory of those killed by Hurricane Maria. (Photo: Ricardo Arduengo/AFP/Getty Images)

In December, Rep. Nydia Velázquez, D-N.Y., and Rep. Bennie Thompson, D-Miss., sent a letter to the Government Accountability Office asking it to assess the death toll to make sure it hadn’t been “artificially suppressed.” Velázquez’s office told Yahoo News that it is continuing to have conversations with the GAO about the timetable for the report. The government of Puerto Rico has also commissioned a report from George Washington University that will provide another estimate of the death toll, and draft results are expected this summer.